Pure silver is a lustrous, white, ductile and malleable metal that occurs in both uncombined form and in ores. This element is highly valued for jewelry, tableware, and other ornamental use. Pure silver is relatively soft and unhardenable. For example, pure silver may have an annealed hardness on the order of 35 Vickers Hardness Number ("VHN"). It has been applicants' experience that this material may not be age-hardened. Thus, pure silver is comparatively soft and unhardenable.
Because of this, it is necessary to alloy silver with other elements in an attempt to increase the hardenability of the resulting alloy. For example, sterling silver typically contains 92.5 weight percent silver, and 7.5 weight percent copper. Whereas pure silver has an annealed hardness of about 35 VHN, applicants' experience is that sterling silver has an annealed hardness of about 80 VHN, and may be selectively hardened to about 110 VHN, a substantial increase over that available for pure silver. However, sterling silver tarnishes easily and is not pure.
Because silver is a precious metal, it is often valued by its purity. Heretofore, it has not been possible to commercially manufacture a fine silver alloy having properties adapted for use as fine jewelry, tabletop and accessories.
To this end, applicants have developed certain fine silver alloys (i.e., alloys having at least 99.5 weight percent silver). In these alloys, the high amount of silver is alloyed with selective elements in comparatively low quantities. However, as demonstrated herein, applicants have developed various alloy compositions that are uniquely hardenable to levels far beyond that possessed by sterling silver and pure silver, and are far more tarnish-resistant than sterling silver.